A screenshot of JetBlue's website from the evening of Nov. 11, 2013. / JetBlue

by Ben Mutzabaugh, USA TODAY

by Ben Mutzabaugh, USA TODAY

JetBlue is putting its money where its mouth is in making a statement about the proposed American-US Airways merger.

The airline rolled out a fare sale today (Nov. 11) in which its fares from Washington's Reagan National Airport (DCA) have been slashed to $55 each way on four of JetBlue's five nonstop routes there. But the airline's goal from this fare sale isn't to fill seats, it's to send a message.

JetBlue is trying to drive home its argument that it thinks a merged American and US Airways should not be able to keep all of their combined number of "slots" at Washington's Reagan National Airport. That airport is one of the few in the United States where access is restricted, meaning flight rights to the close-to-downtown are highly coveted by most U.S. airlines.

In its e-mail announcing its $55 sale to D.C. customers, JetBlue notes that "the new American would control 68% of the slots at DCA. We don't think that's fair. We think the new American should be held to the current US Airways' level of slots. That would be 55."

JetBlue goes on, adding: "Just to make sure Washington gets the message, we put together this nice sale for you! Fares from $55 to Boston, Fort Lauderdale, Orlando and Tampa. Hope you can 'slot' a trip in between November 12 and December 18! Tickets must be purchased by November 12."

And, as in most fare sales, there is considerable fine print for those hoping to snag the lowest advertised sale fares. In JetBlue's D.C. sale, the $55 fares are only available on Tuesdays and Wednesdays . Except on December flights to Tampa, the availability of the those fares was generally good as of 6 p.m. ET on Monday (Nov. 11). Fares on other days of the week were higher, but could be combined with the $55 fares.

US Airways fliers also can take advantage of the sale. US Airways -- one of the targets of JetBlue's sale -- matched JetBlue's prices on all four routes, according to fare search on Kayak.com conducted 6:20 p.m. on Monday (Nov. 11).

For those unfamiliar with the airline terminology, a "slot" gives an airline the right for a single takeoff takeoff or landing. A pair of slots allows a round-trip flight. An airline with 30 slots, for example, would be allowed to operate 15 round-trip flights a day. Slot-controlled access is unusual airports in the U.S., where only a small number are subject to such restrictions. In addition to DCA, some of the most-notable others include New York LaGuardia, New York JFK and Newark Liberty.